• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.52-52
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• 2022

Recently, PE (polyethylene) film has been used increasingly in com cultivation. However, PE films often cause soil and environment contamination. In order to reduce this problem, many researches have been carrying out studies on biodegradable films (BF) that are easily decomposed by soil microorganisms. Therefore, this study was conducted to determine which BF is optimal for growth and yield of com crops while also having the highest rates of film decomposition. BFs Farmsbio (Farm Hannong), Heulgro Film (Sejin Bio), Vonto Film (Eco-Hansung) as well as a selected PE film were used in this study. For the control, we used crops grown without any kind of mulching. Experimental fields were fertilized according to conventional cultivation methods, tilled, and then covered by either BF or PE. After 1 week, com (cv. MIBECK2ho) at the 3-leaf stage (16 days after seeding) was transplanted. Plant height was measured at 18 and 32 days after transplanting and heading stages. Yield components and yield were also measured at harvest. In addition, pH, EC, and decomposition and light transmittance levels of films were investigated during the experimental period. Daily average temperature, relative humidity and organic matter in soils were also measured during the experimental period. There was no significant difference in plant height, heading date, and silking between crops with BFs and PE, but the crops grown with BFs and PE films reached higher growth parameters in a shorter amount of time than the crops in the non-mulching control. Additionally, there were no significant differences in yield components such as length of ears, ear width, ear weight, and yield in crops that were grown using films or crops in the control plot. Light transmittance and decomposition levels of films generally increased with time after transplanting, and was highest in the Heulgro film than other BFs. Soil pH and organic matter in crops using BFs and PE films were significantly higher than in the control plot at 99 and 113 days after transplanting. In general, the EC contents in the control plot was lower than in crops using BFs and PE films. The average daily moisture in soil was higher when BFs and PE films were used than in the control plot. However, the daily average soil temperature was higher in crops using BFs and PE films than in the control plots at the beginning of the experimental period, but there was no consistent difference in soil temperature towards the later part of the experimental period. Therefore, the BFs used in this study were shown to be helpful without causing negative impacts on the growth and yield of com.

• Korean Journal of Organic Agriculture
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• v.5 no.2
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• pp.85-91
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• 1997

This experiment was carried out to investigate the effect of slow-release fertilizers on yield of lettuce. Fertilizers were treated with CDU, MEISTER, Jobi Gohyungbokhapbiryo, Kyungki Wonyebokbi 1ho, Kyungkibokbi Nojeok, Kyungki Jeonjakgohyungbokbi, Traditional manuring, and No manuring. Yields of Spinach was increased with slow-release fertilizers, also. But analysis of chemical components of plants and soil were no difference. It was very effect to increase yields of lettuce, to reduce in number of supplementary manuring and laboring.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.752-761
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• 2011

Recently, upland crops cultivation instead of paddy crops are more popular and highlighted by increase of social demand in agricultural land use. Especially, wheat cultivation for replacing of import food grain are more interested by government, and it is urgently needed that possibility of wheat cultivation is evaluated in the reclaimed tidal land. Crop cultivation is closely related with soil salinity and cultivation method in the reclaimed tidal land. In order to evaluate possibility of wheat cultivation, effect of different application level of compost and nitrogen additional fertilizer, also soil salinity on the grain yield and yield components of three wheat cultivars was studied at the newly reclaimed Saemangeum and Hwanong tidal lands in Korea. $270-300kg\;10a^{-1}$ of grain yield were obtained at the experimental site in the Saemangeum reclaimed tidal land where soil salinity was less than $4dS\;m^{-1}$ during growing periods from December, 2009 to June, 2010. However, almost no grain yield was obtained at the experimental site in the Hwaong reclaimed tidal land, where soil salinity was more than average $8dS\;m^{-1}$ ranged from 2.0 to $25.9dS\;m^{-1}$ during growing period and then salt demage was severe. Yield was significantly different among application level of compost and nitrogen additional fertilizer in the newly reclaimed Saemangeum tidal land. However, it is considered that three cultivars such as Chopum, Chogyung and Geumgang, have similar sensibility to soil salinity and fertilizer level, because there is statistically no difference among ciltivars in Hwaong and Saemangeum, and also among cultivars in the different levels of compost and fertilizer. Finally, it is concluded that wheat can be possibly produced by reasonable fertilizer application in the Saemangeum reclaimed tidal land, but wheat cultivation is impossible because of high soil salinity in the Hwaong reclaimed tidal land.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.04a
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• pp.122-123
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• 2000

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.04a
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• pp.90-91
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• 2000

• Korean Journal of Materials Research
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• v.32 no.10
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• pp.403-407
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• 2022

This research investigated the effect of Si addition on the microstructure, mechanical properties, electric and thermal conductivity of as-extruded Al 6013 alloys. As the content of Si increased, the area fraction of the second phase increased. As the Si content increased, the average grain size decreased remarkably, from 182 (no Si addition) to 142 (1.5Si), 78 (3.0Si) and 77 ㎛ (4.5Si) due to dynamic recrystallization by the dispersed second particles in the aluminum matrix during the hot extrusion. As the Si content increased, the yield strength and ultimate tensile strength increased. The maximum values of yield strength and ultimate tensile strength were 224 MPa and 103 MPa for the 6013-4.5Si alloy. As the amount of Si added increased, the electrical and thermal conductivity decreased. The electrical and thermal conductivity of the Al6013-4.5Si alloy were 44.0 % IACS and 165.0 W/mK, respectively. The addition of Si to Al 6013 alloy had a significant effect on its thermal conductivity and mechanical properties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.403-408
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• 1987

The milled rice yield of the fertilized Zeolite in the sandy loam as 542 Kg/10a was increased by 11% compared with the check plat as a standard cultivation. Significant positive correlations of that were found between grain yield/plant and panicle/total weight ratio or average weight of panicle, while lower correlations between ratio of riqened grains and grain yield/ plant. But significant negative correlations were found between 1,000-grain weight of rough and 4th. 5th internode/culm length ratio. It was reavealed that there were higher direct effects for ratio of ripened grains and spikelets/panicle affecting grain yield/plant through path analysis among the yield components. Moreover, organic dry matter production at 35 days after heading were heavier by 26% in active leaves, 19% in stem + leaf sheath, and 5% in panicle, respectively. Ratio of settled spikelets on the terminal of primary rachis-branch was 47% to total spikelets, and 37% in half-upper of that, moreover many spikelets settled on the terminal of rachis. Therefore, it was recognized that there were a dominant effect of apical glumous flower by fertilized Zeolite.

• Proceedings of the Korean Society of Crop Science Conference
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• 1995.05a
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• pp.22-23
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• 1995

• Proceedings of the Korean Society of Crop Science Conference
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• 1990.05a
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• pp.114-115
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• 1990

• Journal of the Korean Society of Tobacco Science
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• v.9 no.1
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• pp.45-55
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• 1987

For some basic information in tobacco breeding, the modes of inheritance and heritabilities for the twelve agronomic and chemical characters were estimated in the study of eight varieties partial diallel set. Additive gene actions were significant for all characters except total nitrogen content and dominance gene effects were also significant for all characters. Yield, number of leaves per plant, leaf length and leaf shape index were inherited as partial dominance, and overdominance was detected for plant height, stem diameter, internode length, total alkaloid, total nitrogen and total sugar content. Dominant gene showed increasing effects in yield, plant height, stem diameter, internode length, leaf width and total sugar content, but showed decreasing effects in the other characters. The broad heritability was very high for all characters. and the narrow heritability was high in days to flower and yield, but low in internode length, total alkaloid, total nitrogen and total sugar content.